Patent GB-349733-A (GB)
IPC: B64C1/00
Filed: 1930-04-22
Abstract: 349,733. Controlling aircraft and watercraft automatically. MESSGERATE BOYKOW GES., 2A, Fontanestrasse, West Lichterfelde, Berlin. April 22, 1930, No. 12469. Convention date, April 29, 1929. [Classes 4, 113 (i), and 114.] A device for automatically stabilizing an aircraft or other vessel and keeping it on a straight or a curved course comprises a main gyroscope adapted to swing the rudder proportionally to the amount of deviation from the course and an auxiliary gyroscope neutrally suspended and responsive to yawing movements by precession about a horizontal axis under resilient constraint, and a non- rigid connection between the two gyroscopes whereby both initially operate to turn the rudder to correct deviation and the auxiliary gyroscope operates to turn the rudder in the opposite direction towards the end of the correcting movement. Means for initiating a turn and for indicating the trim of the aircraft also are provided. The main gyroscope has a horizontal spinning axis 2 and is mounted on a vertical axis 3 in a ring 5 pivoted about a horizontal axis 4 parallel to the longitudinal axis of the machine. The gyroscope is made pendulous by an electromagnet system 6 fixed to the ring 5. The axis 3 has an arm 9 co-operating with contacts 7, 8, carried by the ring 5 and the axis 4 has an arm 12 co-operating with contacts 10, 11 on the machine. The auxiliary gyroscope 13 has a horizontal spinning axis and is mounted on a horizontal longitudinal axis 14 on which a lever 15 is mounted, a spring 18 opposing any precession about the axis 14. The lower end of the lever 15 controls a reversible motor 57 for actuating the rudder and the upper end is connected by a link 19 to an arm on a rotary relay 20 controlled by precessional movements of the main gyroscope about the axis 3. These precessional movements are caused by the lateral accelerations produced when the machine turns off its course acting upon the mass of the electromagnet system 6 thereby producing a torque about the axis 4. As the speed of deviation becomes checked the spring 18 begins to pull back the arm 15 towards its normal position and as the machine begins to return to its course the arm 15 is displaced in the opposite direction to reverse the displacement of the rudder and check the return swing whereupon the arm 15 is again pulled to its neutral position and the reversed acceleration restores the arm 9 to its mid position. The contacts 10, 11 control the ailerons and as the contacts are fixed to the machine they follow up the contact arm 12. To cause the aircraft to assume a curved course the electromagnet system 6 is energized to exert a torque in the appropriate direction about the axis 3 of the main gyroscope. This is done by depressing either of two keys 24, 25 to energize one of two coils 21, 22 in the electromagnet system 6 whereby a polarized armature 23 on the axis is turned. This results in precession about the axis 4 but as this is resisted by the weight of the magnet system 6 precession about the axis 3 results and the relay 20 is actuated. To overcome the effect of the auxiliary gyroscope and to ensure the turn being taken up quickly additional current is supplied to the relay 20 through resistances 40, 41 and a contact arm 36 on an axle 31 which is turned by a toothed disc 30 when either key 24 or 25 is depressed. This is done through gearing 35, 34 driven through a reversible clutch 33 by a continuously rotating motor 32. Another arm 37 moving over contacts 42, 43 actuates the elevator. The applied torque on the shaft 3, however, is so adjusted that the machine remains underbanked for the turn and the resulting outward acceleration causes the arm 9 to precess in the same direction as the turn, and any deviation of the machine from this rate of turn is corrected in the same way as deviations from straight flight until the turn is straightened out by depressing the opposite key. A line 46 on the disc 30 acts as a bank indicator by suitably choosing the motor speed and gear ratio ; the speed of the turn or its radius may also be read on suitable scales. Should a turn persist after the line 46 has been brought to its horizontal position, owing to accumulated errors, a switch 48 having contacts 49, 50 enable a torque to be applied to the axis 3 through the armature 23 so long as the arm 9 is on either of the contacts 7, 8. Resistances 51 prevent actuation of the clutch 33 when the switch 48 is actuated. Resistances 52 enable the current through the relay 20 to be correctly adjusted, and a resistance 53 with a slider 54 enables a permanent correcting torque to be applied to the armature 23 for any purpose such as the correction of the effect of the earth's rotation. By moving a switch 26 the automatic control is cut out and the main gyroscope, by energizing either of two windings 55, 56, then controls the keys 24, 25 to adjust the disc 30 which acts as a bank and turn indicator as the machine is manually controlled.